const path = require('path')
const pathStr = path.join('a', 'b', 'c', '../', 'd')
console.log(pathStr)
const fs = require('fs')
fs.readFile(path.join(__dirname, './files/1.txt'), 'utf8', function(err, dataStr) {
  if (err) {
    return console.log(err.message)
  }
  console.log(dataStr)
})